At least nine oil tankers carrying fuel for NATO forces stationed in Afghanistan have been destroyed in a fire in southwestern Pakistan.

Pakistani officials said the incident occurred on September 15 near the town of Hub in Balochistan Province, bordering Afghanistan and Iran.

No one was reported killed or wounded.

It remains unclear what caused the fire. Some reports say it was triggered by an explosion in one of the vehicles.

A police official said a group of militants fired rockets at the tankers.

But district police officer Lasbela Ahmad Nawaz Cheema said no gunfire was heard in the area. He did not rule out possibility of a blast caused by improvised explosive device.

The Taliban has in the past carried out such attacks to disrupt supplies for U.S.-led NATO troops fighting in Afghanistan.

In Balochistan last week, gunmen fired bullets and rockets at a convoy of 15 NATO oil tankers traveling from Pakistan's main seaport of Karachi to Afghanistan. Local officials said a driver was killed and eight vehicles were set on fire.

Pakistan and the United States have signed a deal allowing NATO supply convoys to travel into Afghanistan until the end of 2015.